- Receipt of concomitant or sequential chemo-radiotherapy, consisting of a minimum of two cycles of platinum-based chemotherapy and a minimum radiation dose of greater than equal to 50 Gray. Subjects must have completed the primary thoracic chemo-radiotherapy at least 4 weeks (28 days) and no later than 84 days prior to enrollment. Subjects who received prophylactic brain irradiation as part of primary chemo-radiotherapy are eligible